Most programs need to exchange data with other programs from time to time.
Many techniques for making this exchange have been used over the years.
Currently, the most popular approach to doing this is to create XML documents
and transfer them to another computer where they can be parsed and the data
processed.

Because XML documents are really text files, you can parse them any way that
you like. Java programmers normally use the parsers that are found in the Java
API for XML Parsing (JAXP). This chapter will introduce you to the use of these
parsers.

XML is a set of rules that govern how you create a special language to
describe your data. These rules provide a set of reserved characters and their
usage in defining a set of tags that identify entities in your world. If you
make up the tags according to the rules of XML, you will have access to a number
of tools that will make parsing your data easier, once you are familiar with
them. Getting you familiar with them is the main goal of this chapter.